1. Field of the Invention
The present invention relates to a bonding apparatus for connecting lead of a semiconductor device to an element, such as a substrate and the like.
2. Description of the Prior Art
FIG. 3 is a partial cross-sectional view showing a conventional bonding apparatus for a semiconductor device, which is disclosed in Japanese Utility Model Laying Open Gazette No. 59-84841, for example.
The apparatus in FIG. 3 is for bonding lead 24 to a semiconductor device 22 mounted on a base 26.
The lead 24 affixed to tape 25 has a junction 24a which is the only exposed portion. The junction 24a is set on the semiconductor device 22 with bonding agent 23 sandwiched between them, and then, a bonding tool 21 presses and heats the junction 24a from above. This causes the bonding agent 23 to fuse, and the lead 24 and the semiconductor device 22 are connected.
The related art includes embodiments disclosed in Japanese Patent Laying Open Gazettes No. 62-67894, 62-276840, 63-157431, and 1-15631.
In the conventional bonding apparatus as mentioned above, the lead 24 and the semiconductor device 22 must be bonded in the atmosphere, and therefore, in bonding them, the oxidation of the bonded junction progresses. Eventually, a bonding with high reliability cannot be obtained.
This is why flux or the like must be used in the bonding. In such a case, however, there are some disadvantages, for example, that scattered flux contaminates a surface of the semiconductor device 22, and it leads to imperfect contact.
Moreover, there also arises the problem that the bonding is performed in such a way that the bonding tool 21 directly presses the junction 24a to heat and melt the bonding agent 23, and therefore, the melted bonding agent 23 adheres to the tip of the bonding tool 21 and contaminates it.